JPH0441496B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor wafer measuring device used in a semiconductor wafer manufacturing process, and particularly to a semiconductor wafer prober.

Conventional semiconductor wafer chips are usually formed in several hundred pieces on a single wafer at the same time, and are individually separated after measurement. From the separated chips, only good chips are taken out and packaged to complete the integrated circuit (IC) product.

To explain this in more detail, in the process of measuring the electrical characteristics of chips within a wafer, an input signal is sent to the chip from a device called a tester, which determines whether the chip is good or defective. It receives the output signal and judges the output signal to judge whether the chip is a good product or a defective product.

Usually, the above input/output signals are sent out from the tester by a stylus (hereinafter referred to as probe card needle) placed on the probe card to match the position of the electrode (hereinafter referred to as pad) provided on the chip, or sent to the tester. The tester receives a signal from the chip and determines whether it is a good product or a defective product, and if it is a defective product, it sends a defect signal to the semiconductor wafer prober. A semiconductor wafer prober operates a device called an inker (marker) that marks the surface of a chip in accordance with the above-mentioned defect signal, and adds a mark to the surface of a defective wafer chip.

Conventionally, such an inker has one or more needles provided in the center of a semiconductor wafer prober. In this case, the tester adds a mark to the surface of the chip judged to be defective in two ways: firstly, it is done immediately after measuring one chip, and secondly, when the tester marks the surface of the chip judged to be defective, it is done immediately after measuring the chip. It is mapped (hereinafter referred to as mapping) and stored in a storage area (hereinafter referred to as wafer map), and when the measurement of all chips is completed, the chips judged to be defective are collectively marked at another location. There are cases where it is done.

Furthermore, the mechanism of the above-mentioned inker is a type in which ink is attached to the chip surface using a needle,
There are two types: one type that damages the chip surface by striking it with a hard needle, and the other type that melts the chip surface by irradiating the chip surface with laser light.

In any of the above three types of marks, when the inker strikes the needle toward the chip during marking, one of the functions of the semiconductor wafer properr is to conduct current and turn it into an electromagnet. The operation of the inker can be understood. However, since it is not confirmed whether the mark has actually been added or not, if the inker is operated when the ink is out, the mark may not have been added. As a result, even defective chips are judged to be good. Also, regarding the type of chip that damages the surface of the chip by striking it with a hard needle, even if the tip of the needle breaks and cannot reach the wafer chip, a defective chip is similarly judged to be a good product. The same goes for the type of laser that melts the chip surface by irradiating it with a laser beam, and there are cases where the laser beam is not emitted due to damage to the tip from which the laser beam is emitted. Therefore, even defective chips are judged to be good.

The purpose of the present invention is to solve these problems by automatically recognizing and confirming whether a defective wafer chip has been marked with a defective mark by an inker when the tester determines that the defective wafer chip is a defective wafer chip. An object of the present invention is to provide a semiconductor wafer prober that can perform the following steps.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing an outline of the semiconductor wafer prober of the invention, Fig. 2 is a plan view showing the surface of a semiconductor wafer, and Fig. 3 is a wafer prober. It is a diagram.

In the semiconductor wafer prober of the present invention, a semiconductor wafer, which is an object to be measured, is placed on a mounting table and fixed by vacuum suction. This mounting table is automatically operated by a drive mechanism that moves in the horizontal X-axis and Y-axis directions and in the vertical Z-axis direction. With the wafer positioned at a predetermined position, the probe card needle is brought into contact with the pad of the chip for measurement. This probe card needle has a measuring mechanism that is connected to a tester to measure whether the wafer is good or bad. This tester measures each wafer chip through a mechanism such as the positioning of a semiconductor wafer prober, and has a judgment function that determines whether the wafer chip is good or bad based on the results of measuring the electrical characteristics of the obtained wafer chip.

The measurement results of the tester determined in this manner are displayed on the wafer by a marking mechanism that adds a defect mark based on a defect signal from the tester. Thereafter, the recognition device recognizes the shape of the defect mark on the wafer as a whole, and the measurement result of the wafer chip within the wafer is stored as a wafer map. Each of these mechanisms is controlled as a whole by a control mechanism. Of course, each individual mechanism itself can be a known one.

In the semiconductor wafer prober of this invention,
The address signals in the X-axis and Y-axis directions in the drive mechanism and the pass/fail signals in the chip measurement results by the tester are stored in a storage area of the control mechanism called a wafer hop as measurement information that associates each chip with an address. As shown in FIG. 2, a defective chip 8 in the wafer 1 is displayed by a defective signal from the tester and mapped to addresses in the X-axis and Y-axis directions. Based on the information stored in the wafer chip, an inker is operated to add a mark to the surface of the defective wafer chip within the wafer. Up to this step, conventional techniques are used.

Note that if the added defect mark is recognized by a recognition device, the information resulting from the recognition may be mistaken for dust, so first, the wafer prober itself memorizes the shape of the defect mark in advance and uses it as a basic defect mark. It's called Mark. Compare this basic defective mark with the added defective mark, and if the shape is along the basic defective mark, it is a defective wafer chip that corresponds to the measurement result by the tester, and it is confirmed that the defective mark has been added to the surface of the wafer chip. It becomes clear. In addition, this defective mark is automatically recognized after the chips in the wafer are measured using a semiconductor wafer prober, and there is a process in which only good wafer chips are assembled, but in this case as well, judgment is made based on the size (area) of the defective mark. Because I often do
In the wafer probing process, it is extremely useful to automatically recognize the size of defective marks.

Here, if the measurement result indicated by the wafer chip is a defective wafer chip and the result recognized by the recognition device is not recognized as a defective mark, a defective mark is added to the surface of the defective wafer chip again by the defective signal. Thereafter, the recognition device recognizes the defective mark again, and as a result, the defective mark is recognized.

In addition, if the above-mentioned inability to recognize continues several times, for example, if a function is installed to notify the operator, the operator can always check that only defective wafer chips have been marked with defective wafer chips by filling ink. , complete the entire process of semiconductor wafer prober.

Since this invention is configured as described above,
A defective mark is added to all defective semiconductor wafer chips except for good semiconductor wafer chips, and since the defective mark is used as a guide when sorting wafer chips, highly reliable quality products can be obtained as semiconductor wafer chips. . It is also very effective in automation.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the semiconductor wafer prober of the present invention, FIG. 2 is a plan view showing an example of a defective wafer chip on the wafer surface, and FIG. 3 is a schematic diagram for explaining the wafer chip. be. 1... Semiconductor wafer, 8... Defective wafer chip.

Claims (1)

[Scope of Claims] 1. Means for measuring each wafer chip provided on a semiconductor wafer, means for storing the measurement results in the wafer chip, means for marking defective chips as a result of the measurement, and recognition of the mark made by the marking. and means for comparing the mark recognition result and the stored measurement result to detect a marking error. 2. The semiconductor wafer prober according to claim 1, wherein the marking means remarks the chip for detecting a chip based on the result detected by the marking error detecting means.